We propose to develop a light source having a spectrum that spans the visible wavelengths, with a beam quality similar to a laser. Our goal is to cover the wavelengths from 400 nm- 700 nm, with at least 1 mW in any 1 nm slice of the spectrum. The light source will be based on an inexpensive diode-pumped mode-locked laser, the output of which is spectrally broadened into a continuum by a highly nonlinear, single-mode, fused-silica fiber. The output of the fiber will be pulses of diffraction-limited white light, with a pulse repetition rate near 100 MHz. Such a high repetition rate is equivalent to continuous light for virtually all instrument applications. Such a source would have many laboratory uses, for example in fluorescence imaging. The spectrum of the proposed source could be filtered to obtain a laser-like beam at any desired visible wavelength. This flexibility would make fluorescence confocal microscopes much more powerful tools, since they could be used at any excitation wavelength.